COLGeek :
See page 17 of the manual:
http://dlcdnet.asus.com/pub/ASUS/nb/E402SA/0409_E10572_E402MA_E502MA_V2_B.pdf?_ga=2.115373958.1877553236.1505262431-2141896587.1505262431
Doesn't show where the battery is. Just says that the battery can't be disassembled. I guess that's their lame way of saying the battery is internal and not accessible by the owner.